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Group 8 is a group (column) of chemical elements in the periodic table. It consists of iron (Fe), ruthenium (Ru), osmium (Os) and hassium (Hs).[1] They are all transition metals.

Group 8 in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
group 7  group 9
IUPAC group number 8
Name by element iron group
CAS group number
(US, pattern A-B-A)
part of VIIIB
old IUPAC number
(Europe, pattern A-B)
part of VIII

↓ Period
4
Image: Iron, electrolytic made, 99,97%+
Iron (Fe)
26 Transition metal
5
Image: Ruthenium bar, 99,99%
Ruthenium (Ru)
44 Transition metal
6
Image: Osmium crystals, ≈99,99%
Osmium (Os)
76 Transition metal
7 Hassium (Hs)
108 Transition metal

Legend
primordial element
synthetic element
Atomic number color:
black=solid

Like other groups, the members of this family show patterns in electron configuration, especially in the outermost shells, resulting in trends in chemical behavior.

"Group 8" is the modern standard designation for this group, adopted by the IUPAC in 1990.[1]

In the older group naming systems, this group was combined with the groups 9 (Co, Rh, Ir…) and 10 (Ni, Pd, Pt…) and called group "VIIIB" in the Chemical Abstracts Service (CAS) "U.S. system", or "VIII" in the old IUPAC (pre-1990) "European system" (and in Mendeleev's original table).

Group 8 (current IUPAC) should not be confused with "group VIIIA" in the CAS system, which is group 18 (current IUPAC), the noble gases.

While groups (columns) of the periodic table are sometimes named after their lighter member (as in "the oxygen group" for group 16), the term iron group does not mean "group 8". Most often, it means a set of adjacent elements on period (row) 4 of the table that includes iron, such as chromium, manganese, iron, cobalt, and nickel; or only the last three; or some other set, depending on the context.

Basic propertiesEdit

Z Element No. of electrons
per shell
M.P. B.P. Year of
Discovery
Discoverer
26 iron 2, 8, 14, 2 1811 K
1538 °C
3134 K
2862 °C
<3000 BCE Unknown
44 ruthenium 2, 8, 18, 15, 1 2607 K
2334 °C
4423 K
4150 °C
1844 K. E. Claus
76 osmium 2, 8, 18, 32, 14, 2 3306 K
3033 °C
5285 K
5012 °C
1803 S. Tennant and
W. H. Wollaston
108 hassium 2, 8, 18, 32, 32, 14, 2 1984 P. Armbruster and
G. Münzenberg

The first three elements are hard silvery-white metals. Hassium has not been isolated in macroscopic pure form, and its properties have not been conclusively observed.

ReferencesEdit

  1. ^ a b Leigh, G. J. Nomenclature of Inorganic Chemistry: Recommendations 1990. Blackwell Science, 1990. ISBN 0-632-02494-1.